There is no uniform and widely accepted definition of harmonic distortion power, in this paper, based a high-frequency welding businesses' data monitored by power quality analyzer three widely accepted definition of harmonic distortion are analyzed and calculated. Also, analysis and calculation of the enterprise's harmonic energy savings after the harmonic treatment is implemented, and the results are compared with the actual measured data, which prove the calculation is reliable, and the calculation is of positive significance to analyze the benefit of enterprise's harmonic governance measures.